The theme of this program project osi based on our model for autism as a disorder of complex information processing resulting from the abnormal development and dysfunction of neocortical systems. This model corresponds to the boundaries and hierarchy of cognition in a information processing model developed by Drs. Carpenter and Just, and recently validated with fMRI. The proposed research will consist of a cross-sectional study of adults and a longitudinal study of children to investigate the maturation of cognitive abilities and neural circuitry. Autistic subjects will be characterized in terms of family history and clinical features most likely indicative of separate genetic subgroups. Project I. Autism As A complex Information Processing Disorder will provide evidence of complex information processing as a clinical mechanism for autism, define the qualitative features of the deficits most specific to autism, and begin the detailed cognitive task analysis in the reasoning domain. Project II. Behavioral and fMRI Studies of cognition in Autism will perform detailed cognitive analyses and fMRI of executive function, working memory, language comprehension, and spatial abilities. Project III. Neural Circuitry of Cortical and Subcortical Systems will use eye movement procedures analogous to those of Goldman-Rakic to investigate neocortical circuitry and additional procedures that evaluate subcortical circuits; fMRI studies will be completed with these eye movement procedures and also with simple and skilled hand movements related deficits in motor praxis in autism. The Adminiistrative Core will provide administrative, scientific and fiscal oversight for the project, and provide a nidus for scientific interactions and growth. The Subject Core will involve a two site recruitment (Case Western Reserve) to identify 200 high functioning autistic and 200 individually matched control subjects; this core will administer all tests for Projects I and II and provide behavioral management and support for all subjects during eye movement and fMRI studies.